Playback or recording mode of a cassette-type tape player is created by engagement between reel holes of a cassette and reel axles vertically standing from a base plate of the tape player. To effect this engagement, several cassette loading arrangements are employed, depending upon whichever direction the cassette is inserted from with respect to the tape player. One of the arrangements is called "horizontal loading" wherein a cassette is inserted horizontally through an opening of the front face of a tape player toward a pack guide, and the pack guide carrying the cassette in position thereon is dropped onto a reel base so as to engage the reel holes with the reel axles.
One of tape players of this type is adapted so that a cassette which is manually pushed up to a certain position on the pack guide is thereafter automatically conveyed to the full extent on the pack guide by a loading/ejection mechanism. One of such loading mechanisms employs a motor power and another employs a spring force to fully engage the tape cassette with the tape guide. Among these, one loading mechanism uses a single inversion spring which pushes the cassette not only backward into the full engagement with the pack guide but also forward to the ejecting position.
FIG. 1 shows a loading/ejection mechanism including such an inversion spring. A guide arm 2 supporting a pack guide 1 has an upper plate which has formed a guide slot 3 elongated back and forth of a tape player and receiving therein a pack stopper 4 engageable with a cassette. An inversion spring 6, a torsion spring, is connected between a pin 4a on the pack stopper 4 and one end of a swing plate 5 rotatably mounted on the guide arm 2. A first end of the inversion spring 6 connected to the pin 4a has an arcuate configuration so as to rotate about the pin 4a. A second end of the inversion spring 6 connected to the swing plate 5 is rotatable in a hole formed in the swing plate 5. The other end of the swing plate 5 is supported by a pivot axle 7. An operation rod 9 connects a central portion of the swing plate 5 to an ejection lever 8 which is manually operated.
The ejection lever 8 is biased forwardly (leftward in FIG. 1A) by a spring 11 fixed to a pin 10 on a frame of the tape player.
An eject lock arm 12 is mounted substantially symmetrically to the swing plate 5 with respect to the pack stopper 4. The eject lock arm 12 is rotatably mounted on the guide arm 2 by an axle 12a. A first end of the eject lock arm 12 has a contact surface 12b to be pushed by the back end of the pack stopper 4. A second end of the eject lock arm 12 which is symmetric to the first end 12b with respect to the axle 12a is connected to a lock plate 13 for locking the pack guide 1 at an elevated position. The lock plate 13 extends back and forth of the tape player and is normally biased backward to the locking position (to the right in FIG. 1). The lock plate 13 has a cutout 15 which consists of narrower and wider halves defined by a step 15b and engages a pin 2a on the guide arm 2. The pin 2a enters in the wider half and rides on the step 15b when the pack guide 1 is fully elevated, but otherwise engages a side wall 15a of the narrower half of the cutout 15 (FIG. 1a).
When a cassette is manually inserted into the pack guide 1, the cassette pushes the pack stopper 4 back into the tape player (to the right in the Figure). The inversion spring 6 connected to the pack guide 4 is compressed, accordingly.
In FIG. 2, the pack stopper has been pushed by a manual force to a position in which the first end of the inversion spring 6 to the right of the second end connected to the swing plate 5. Since the swing plate 5 is now kept unrotatable, the expansion force of the inversion spring is oriented backward (to the right in the Figure), or in other words is inverted as to the pack stopper 4, and automatically fully pushes the pack stopper 4 and the cassette carried thereon to the innermost (rightmost) end of the tape player.
Along with the backward movement, the pack stopper 4 pushes the first end 12b of the eject lock arm 12 and rotates it in the clockwise direction about the axle 12a. Therefore, the second end of the eject lock arm 12 moves the lock plate 13 forwardly against urging of a spring 14. The pin 2a of the guide arm 2 is thereby allowed to drop from the step 15b and engage the side wall 15a of the narrower half of the cutout 15. Therefore, the pack guide 1 can drop onto the reel base with the energy of the spring 11 biasing the ejection lever 8. When the pack guide 1 fully drops to a position whereat the pin 2a reaches the open end of the cutout 15, the cassette loading is completed.
For effecting a cassette ejecting operation, the ejection lever 8 is depressed to elevate the pack guide 1. With this depression, the pin 2a moves back along the side wall 15a and enters into the wider half of the cutout 15. The lock plate 13 which was locked at the forward position by engagement between the side wall 15a and the pin 2a is allowed to return to the backward position with the energy of the spring 14. The pin 2a then engages the step 15b and locks the pack guide 1 at the elevated position. The eject lock arm 12 linked to the lock plate 13 rotates in the counterclockwise direction so as to move the end 12b thereof forwardly.
At the same time, the depression of the ejection lever 8 is transmitted to the swing plate 5 via the operation rod 9. The swing plate 5 rotates in the counterclockwise direction while compressing the inversion spring 6, until the second end of the inversion spring 6 comes to the right of the first end connected to the pin 4a of the pack stopper 4. As the result, the pack stopper 4 is pushed forward together with the cassette by the expansion energy of the inversion spring 6. After this, when the ejection lever 8 returns to the left due to the energy of the spring 11, the swing plate 5 and the pack stopper 4 connected thereto via the inversion spring 6 rotate or move forward and eject the cassette from the pack guide 1.
The prior art, however, involves the following problem. The ejection mechanism using the inversion spring 6 cannot perform its reliable operation unless application of forward pressure to the cassette by the inversion spring 6 coincides with locking of the pack guide 1 at the elevated position. In the prior art mechanism, however, since the pack stopper 4 and the eject lock arm 12 are not directly interlinked during the ejecting operation, a time lag therebetween causes the following problem. Namely, if the inversion spring pushes the cassette forward earlier, the pack stopper 4 starts to move to the left before the pack guide 1 is fully elevated. If a manual force continues to push the ejection lever after the spring is inverted and until the pack guide 4 is fully elevated to the lock position, no problem will occur. However, if the manual force is removed halfway through this sequence, the pack guide 1 drops onto the reel base again, and sometimes forcibly pins down the cassette which already started to move forward to the ejection position due to the inversion spring. In this state, if a user dares to manually pull the cassette by force, it will lead to a great damage of the tape player. Alternatively, even if the user can barely take it out, he cannot reinsert a cassette because the pack guide 1 which dropped onto the reel base remains there.